Underground Turin: the tunnels of Pietro Micca

It may be hard to imagine today, but Turin was, at one time, a fortified city. The first stone of the fortification was laid in 1564, on the orders of Duke Emanuele Filiberto, who wished to protect his new capital.

The Citadel was laid out in a pentagon shape, with a stronghold at every angle, and surrounded by a wide moat.

In 1706, in the middle of the Spanish war of succession, the Citadel was attacked by more than forty thousand soldiers of Louis XIV, and was able to repel the assault due to the well-planned defense system beneath the city. In fact, 14 kilometers of tunnels had been dug, consisting of main tunnels (the deepest levels) and service tunnels (closer to the surface).

Recessed areas were dug into the tunnels, and then packed with explosives, which were then ignited as necessary by a slow-burning fuse. The explosion, calculated with the utmost precision, reverberated upwards, just beneath with enemies’ cannons. This was an effective and nearly invisible method of defending Turin, which Field Marshal Vauban, a famous military engineer, defined as the “the quibble of the mines”.

These defensive tunnels under the Citadel made one particular soldier famous – Pietro Micca, of the miners’ company. On the night between 29 and 30 August 1706, a battery of French grenadiers found the entrance to the service tunnel and entered it. Micca knew he had to stop them. If they reached the lower tunnel, they would have had easy access to the heart of the Citadel and could have taken it from inside.

He was alone, and therefore unable to stop the enemy with force. Micca decided to ignite a short fuse, causing an immediate explosion that destroyed the stairs leading to the lower tunnel. The explosion prevented the French soldiers from entering the Citadel, but also resulted in the death of Pietro Micca, who was hurled into the air by the strong blast wave and choked by fumes.

A section of the tunnels, including the part in which Micca’s body was recovered, can be visited at the Pietro Micca Civic Museum, in central Turin.

Venturing into the underground tunnels feels a bit like being granted access to a secret spot, hidden from the world. The air is cold, regardless of the weather outside, and the only light comes from the few lamps that are hung along the route. The ceilings are so low that you are forced to bow your head and, at about shoulder height, there are bricks that stick out from the walls that the soldiers used to feel their way along the tunnels when it was necessary to turn out the lights.

There are many details that narrate the precision that was involved in designing the military defense. For example, the stairs that connect that service tunnel to the lower main tunnel were made from small amounts of stone, but mostly from wood, so that, in the event of a threat from the enemy, the wood could be destroyed, rendering the stairs so disconnected that they were virtually unusable.

The Museum also includes a display of weapons, including a French cannon, as well as models of the Citadel and all of the tunnels.